Commonly, door locks, exit alarms, panic devices, and other locking systems employ mortise cylinders that typically are operated with a key placed in a rotatable key cylinder portion of the mortise cylinder. Such assemblies often are installed on a wall or a door. To minimize the size, lock and alarm assemblies must be compact. This introduces a number of difficulties in the design and assembly of such devices.
Typically, an alarm or lock assembly comprises a plate (or cover) that covers the alarm or lock and the mortise cylinder disposed therein. A bracket is secured to the interior of the plate. The bracket and plate cooperate to form a housing for the mortise cylinder and alarm. Typical mounting of the housing is achieved with mounting screws. The mortise cylinder is commonly secured to the bracket by a hexagonal nut engaging threads formed on the exterior of the mortise cylinder. Keys and corresponding key ways, as well as set screws, are methods of securing the mortise cylinder to the housing to prevent rotation of the mortise cylinder.
During assembly of the alarm, the mortise cylinder and associated cam must be carefully positioned relative to one another in the housing to insure proper engagement between the mortise cylinder and cam. Therefore, reliable operation can be difficult to achieve with the alarm assemblies due to the complex installation configuration.
Additionally, there are varieties of mortise cylinder lengths that are in common use. Specifically, there are 5, 6, and 7 pin mortise cylinders that have different lengths. Therefore, depending on the length of the cylinder, adjustments are made during assembly. These adjustments may require a substantial amount of labor and expertise.
To avoid some of these problems, numerous attempts have been made to address the shortcomings of conventional locks and alarms. Some examples of these attempts are listed and discussed below.
U.S. Pat. No. 5,335,520 issued to Lee (“Lee”), discloses a flat lock system that will not be easily picked, in particular where the tumbler is not permitted to pivot with respect to the cylinder. It consists of a cylinder, a tumbler, and several rings and springs. The cylinder has an inner surface formed with a number of separate ribs defining passages that extend perpendicular to the length of the cylinder. The tumbler consists of a disk defining a keyhole, and it is integrated with a key receiver and a latch carrier. The rings and springs are alternatively mounted on the key receiver. Each ring has an outer rim with a number of ears and an inner rim with a number of arms. The purpose of the springs is to bias the rings towards the disk such that the ears protruding from the rings are trapped in the passages between the ribs. When a key is inserted in the key receiver, shoulders formed on the key push the arms on the rings such that the ears protruding from the rings align with the passages formed between the ribs to make the tumbler and latch pivotable.
U.S. Pat. No. 5,265,453 issued to Konii et al. (“Konii”), discloses a tamper and damage resistant cylinder lock. The lock comprising an axial cam provided on a key cylinder, a rotator for engagement with a sleeve and in contact with the axial cam, a stopper positioned adjacent to the rotator having a pair of lugs engageable with a recess of the casing, and an axial spring positioned between the stopper and a connector for resiliently urging the stopper toward the rotator. The rotator and stopper are axially moved by the axial cam to disengage the rotator from the sleeve and the stopper from the casing upon independent rotation of the sleeve on insertion of the correct key. The key cylinder, the rotator, the stopper and connector are rotated as a unit to a locked or unlocked position.
U.S. Pat. No. 4,759,204 issued to Neyret (“Neyret”), discloses a lock mechanism designed to improve security, especially against forceful rotation. It consists of a housing with a bore, a sleeve within the bore, and a rotor which is rotatably mounted and axially slidable within the sleeve. The rotor has a longitudinally extending key slot. A piston slides axially within the bore in the sleeve and rotor between a first rest position where the sleeve and rotor are coupled together for simultaneous rotation, and a second disengagement position resulting on insertion of appropriate key where said sleeve and rotor are uncoupled. Upon removal of the key, a spring pushes back the piston and the rotor towards the rest position.
U.S. Pat. No. 4,581,909 issued to Weber (“Weber”), discloses a cylinder lock, particularly a steering-wheel lock for a motor vehicle. It comprises a locking disk that is displaceable parallel to itself, axially movable on a projection of a cylinder core, and which is at right angles to the axis of the lock. The locking disk can be mounted very securely as it needs only make a sliding movement in relation to the cylinder core, and does not need to turn relative to the cylinder core. Thus, the ‘ready-to-lock-position’ of a locking or transmission member is not cancelled by a tilting or turning of the locking disk, but solely by movement in the axial direction. Moreover, the cylinder lock is connected to a cam that forms a bearing surface for the locking disk. A conical coil compression spring disposed upon an axial extension of the cylinder core urges the locking disk in the direction of the cam upon insertion of appropriate key.
U.S. Pat. No. 4,573,334 issued to Crepinsek (“Crepinsek”), discloses a deadbolt lock adjustable for mounting in doors of various thicknesses. It is an improvement of the deadlock of the type which is mounted in a door and has a lock body with a bore that provides secure access to the dead-bolt throw or retract mechanism. The improvement comprises coupling means non-adjustably and non-rotatingly mounted within the bore of the lock body and extending a preselected distance beyond the outer boundary of the bore, just sufficient to accommodate the thickness of a particular door. One disadvantage of Crepinsek, however, is that there is no system that self-adjusts to a range of depths, depending on the thickness of the door. Hence, Crepinsek requires preselection of a distance prior to installation.
U.S. Pat. No. 4,359,886 issued to Evans et al. (“Evans”), relates to cylinder type key locks and locking devices that are environmentally exposed. It discloses a key mortise cylinder for possibly contaminated environments. The mortise cylinder is a key operated rotary core cylinder lock having rotary disc tumblers arranged in a pack with intervening spacers inside of a rotary core sleeve which is held against rotation within the lock casing by a locking bar.
U.S. Pat. No. 4,196,605 issued to Garza (“Garza”), relates to improvements in tumbler pin-type cylinder locks provided with safety means to reduce the chances that the lock can be picked or rendered ineffective. It discloses a tumbler pin-type cylinder lock with axial or axial and radial cylinder movement. The cylinder moves axially or axially and radially with respect to the lock housing. Movement of the mortise cylinder in the axial direction is brought about by spring means—a helical compression spring constantly urges the cylinder towards the front end of the lock housing, and upon insertion the appropriate key moves the cylinder against the urging of the spring.
U.S. Pat. No. 4,077,240 issued to Crasnianski (“Crasnianski”), discloses a cylinder lock of the type having a stator with a rotor and lamellae actuated by a flat key. The rotor comprises floating lamellae capable of moving radially and angularly, and means for guiding the flat key over its entire introduction path into the rotor without any possibility of lateral or radial displacement. The lamellae are released as a result of the axial pressure applied to the rotor by the key against the action of a spring.
U.S. Pat. No. 3,724,244 issued to Schaumburg (“Schaumburg”), discloses a lock actuated anti-theft device mainly for automobiles. A system of rollers is provided in the direct vicinity of the key hole portion of the lock. Operation of the key causes internal shifting of the rollers causing other lock portions to go into locking position, where the locking position is fully established upon total removal of the key from the lock.
U.S. Pat. No. 3,382,688 issued to Wellekens (“Wellekens”), discloses a lock for vending machines or the like. The lock consists of a plurality of concentric sleeves in nested relationship, where the outermost sleeve constitutes a lock casing, the innermost sleeve carries a locking mechanism that controls a latch, the intermediate sleeve is coupled to the inner sleeve by a rotatable cup having a shoulder under which the latch is advanced for the sleeves to be completed nested. A spring advances the joined inner and intermediate sleeves partly out of the outermost sleeve when the latch is disengaged.
U.S. Pat. No. 3,089,329 issued to Kerr (“Kerr”), discloses an alarm assembly for a refrigerated cabinet or the like. It consists of a draw alarm assembly having a nestled handle and a connecting cam between the handle and a draw shaft. This connection allows for a positive drive between the handle and draw shaft during door tightening operations, but permits for a limited degree of reverse movement of the handle after the tightening operation has been completed.
U.S. Pat. No. 3,026,385 issued to Davis, et al. (“Davis”), relates to an improved push-button operator with locking means. It discloses a push-button operating mechanism comprising a tubular casing, a push-button mounted in the casing for reciprocal movement, a lock barrel mounted in the outer end of the push-button and rotatable upon insertion of appropriate key. The lock barrel is rotatable to one position when the push-button is in its outwardly extended position, and it is rotatable to another position when the push-button is depressed inwardly. A torsion spring urges the lock barrel to rotate upon insertion of the key in and and causes the change from a depressed to an extended position of the push-button.
Even with the numerous attempts to improve locks, there remain a number of shortcomings with these attempts. Accordingly, a need exists for alarm and lock assemblies using a conventional mortise cylinder with a tailpiece on its distal end that minimizes the number of parts in the assembly and simplifies installation on a door or wall.